摘要
采用与母材同质的焊丝对AZ31B镁合金板材进行手工钨极氩弧焊,利用专门设计的模具对镁合金熔焊接头进行423K弯曲变形试验,通过光学显微镜、扫描电镜及拉伸试验机等手段,研究了弯曲前、后的AZ31B镁合金熔焊接头的微观组织及力学性能。结果表明:AZ31B镁合金熔焊接头经423K弯曲变形后,焊缝区和热影响区都出现了一定的孪晶,接头热影响区铸态枝晶组织转变为细小的孪晶组织,孪生成为接头主要的变形机制;焊缝近表面处孪晶密度比中部密度大,焊缝及热影响区晶粒明显得到细化;接头抗拉强度由原先的178MPa增加至216MPa,伸长率由7%提高到9%。
AZ31B alloy sheets were welded by manual tungsten insert gas （TIG） welding method using AZ31B wire as the filler material. The welded joints were bended at 423K. The microstructure and mechanical properties of the welded joints with and without bending were analyzed using optical microscope （OM）, scanning electronic microscopy （SEM）, and tensile test. The results show that after bending, some twins form in the welding zone and heat affected zone, and the as-welded dendrite microstructure of the heat affected zone transforms into the fine twin grains. Twinning is the dominant deformation mechanism. High density twins in the regions near the surfaces of the welding zone form and lower density ones in the center of the welding zone .The grains in the welding zone and heat affected zone were obviously refined. The tensile strength of the welded joints after compound bending increases from 178MPa to 216MPa, and the elongation of the welded joint increases from 7% to 9%.
出处
《热加工工艺》
CSCD
北大核心
2012年第21期5-7,共3页
Hot Working Technology
基金
南京工程学院科研基金资助项目(QKJA2010002)
江苏省自然科学基金资助项目(BK2009354)
大学生科技创新基金资助项目(N20120205)
